Spark-plug.



F. W. SMITH. SPARK PLUG.

APPLICATION FILED JUNE 22, 1908.

925,239. Patented Jun 15,1909;

WITNESSES INVENTOH fled WAY/72am A TTOHNE Y S FRED WILLIAM SMITH, or ABERDEEN, SOUTH DAKOTA SPARK-PLUG.

Specification of Letters Patent. Application filed. June 22, 1908.

Patented June 15, 1909. Serial No. $39,717.

To all whom it may concern:

Be it known that I, FRED WILLIAM SMITH, a citizen of the United States, and a resident of Aberdeen, in the county of Brown and State of South Dakota, have invented a new and Improved S ark-Plug, of which the following is a full, 9 ear, and exact description.

This invention relates to spark plugs adapted for igniting explosive mixtures and more particularly to such as have a casing forming the outer electrode, a removable insulating core and a central electrode, the latter being so formed at its lower end that a spark may pass to the lower end of the casing upon the closing of an electric circuit.

The object of-the invention is to so con struct the lower ends of the casing and central electrode that any soot or oil whichmay collect at the spark gap, upon either of them, will'immediately be drawn ofi'.

The invention consists in the construction and combination of parts to be more fully described hereinafter angl particularly set forth in the claims.

Reference is to be had to the accompany ing drawing forming a part of this specifics; tion, in which the figure shows a side elevation of anembodiment of the invention, having the casing in longitudinal section.

1 represents the casing of the device, of any suitab e conducting material such as iron, steel or the like, and consisting of an extended portion 2 having an interiorly threaded portion 3-, of a body 4 externally threaded to engage a correspondingly threaded opening in the cylinder, and a lower portionof lesser internal diameter 5 and a constricted opening 6 is formed between tlie body and the ortion 5 by an inwardly dis osed, annular ange 7. The inner face of t e lower portion 5 is doubly curved, as shown in the drawing. The body 4 has openings 8 above the flange and connecting with the interior of the cylinder so that the mixture may enter to cause a more perfect explosion.

I provide the spark plug witha core 10 of insulating material held in place by an annular gland 11 suitably threaded to engage the similarly threaded portion 3 of the casing. The core may seat upon a gasket 12 of any suitable material, such as copper, asbestos, rubber or the like, serving to effect a gas tight joint. Extending through the core is the central electrode, having its upper end 13 suitably thrczuled to form the post of the spark plug, on which the customary binding vnections in place.

point to draw off --the end of the core, said insulating core,

nuts 14 are arranged t9 hold the wire con- The lower end 15 of the extends from the core portion 5 of the casing.

central electrode through the lower At a point adjacent to thefiange 7 which forms the constricted, opening 6 the central electrode has a projection 16 from which the s ark jumps to the flange 7 across the ga he free end 17 of the electrode acts as a drlp any oil or soot which may collect near the spark gap. The lower end 15 is of reduced diameter at apoint a short distanceabove the projection 16, and the upper surface of the rojection extends substantially horizontall so that the oil or other li uld in flowing down the central electrode W1 I tend to avoid the projection and assume a course toward the opposite side of the central electrode therefrom. The upper side of the flange 7 is substantially horizontal, while the lower side thereof curves away from the celntral electrode to facilitate the flow of the Q1 Having thus described my invention, I 5

claim as new and Patent 1. A spark plug comprising acasing and an insulating core, the casing having a portion of lesser internal diameter extending beyond casing being provided with an'inge nal annular flange at the junction of the portion of lesser diameter therewith, and an electrode extending beyond the core and into the portion of lesser internal diameter, said electrode being provided with a substantially horizontal projection at the level of the flange.

2. Aspar desire to secure by Letters of lesser internal diameter extending beyond the end of the core, said casing being provided witha'n internal annular flange at the junction of the portion of lesser diameter therewith, and an electrode extending beyond the core and into the portion of lesser diameter, said electrode being provided with a substantially horizontal projection at the level of the flange, the casing being provided with openings above the flange.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

' FRED WILLIAM SMITH.- Witnesses:

W. I. HULETT, J. M. LAwroN.

plug comprising a casing andan I the casing having a portion 

